Communicating encoded traffic data

ABSTRACT

An electronic device encodes traffic data as a collection of codes. The electronic device sends the codes in random access resources or shared transmission resources over a wireless link to a wireless access network node, the codes providing an encoded representation of the traffic data.

BACKGROUND

Various different types of electronic devices can perform wirelesscommunications in a wireless access network. Examples of such electronicdevices include user equipments (devices used by users), sensor devices(which collect measurement data for communication to one or morerecipient systems), and so forth. As the number of electronic devicesserved by a wireless access network increases, the increased burdenplaced on the wireless access network may lead to poor communicationsperformance.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments are described with respect to the following figures.

FIG. 1 is a block diagram of an example arrangement including sensordevices, user equipments, and wireless access network nodes according tosome implementations.

FIG. 2A is a flow diagram of a process of a server device, according tosome implementations.

FIG. 2B is a flow diagram of a process of a wireless access networknode, according to some implementations.

FIG. 3 schematically depicts encoding traffic data into a sequence ofcodes, in accordance with some implementations.

FIG. 4 schematically depicts encoding traffic data for sensor devices indifferent groups into respective different sequences of codes, inaccordance with further implementations.

FIG. 5 is a message flow diagram of a process of communicating codes fortraffic data in respective random access resources granted by a wirelessaccess network node, in accordance with some implementations.

FIG. 6 schematically depicts encoding traffic data of multiple sensordevices, in accordance with some implementations.

FIGS. 7 and 8 schematically depict the selection of subsets of sequencesfor transmission from sensor devices to a wireless access network node,in accordance with some implementations.

FIG. 9 schematically depicts encoding data fields of traffic data totransmit to a wireless access network node, in accordance with furtherimplementations.

FIG. 10 is a block diagram of an arrangement that includes an electronicdevice and a wireless access network node, in accordance with someimplementations.

DETAILED DESCRIPTION

Sensor devices can be used to measure different types of parameters.Examples of such parameters include temperature, pressure, gasconcentration (e.g. concentration of a hazardous gas), strain of amechanical structure, and so forth. Some sensor devices can be placed atfixed geographic positions. Other sensor devices may be mobile, and canmove around within a coverage area of a wireless access network.

The number of sensor devices to be supported by a wireless accessnetwork may exceed the number of traditional user equipments (e.g.telephone handsets, smartphones, personal digital assistants, notebookcomputers, tablet computers, etc.). It is expected that a nextgeneration wireless access network may be expected to support a numberof sensor devices that can be several orders of magnitude greater thanthe number of traditional UEs.

A wireless access network can serve a number of coverage areas (alsoreferred to as cells or cell sectors). Traditional wireless accessnetworks are designed to accommodate the communication and usage modelassociated with UEs. However, the characteristics of sensor devicecommunications may differ from the characteristics of UE communications.For example, sensor devices generally report data intermittently and atunpredictable times, such as when a sensor device is programmed toreport data only if measurement data collected by the sensor deviceexceeds a predefined value or a rate of change. Sensor devices may alsohave reduced mobility, since sensor devices may be deployed at fixedlocations or can be used within a restricted area (such as in a home, astore, a warehouse, and so forth). Additionally, sensor devices mayoperate on battery power that cannot be easily recharged, such that itis desired that communications of sensor devices consume as littlebattery power as possible.

The amount of data communicated by a sensor device can be relativelysmall when compared to the amount of data communicated by a traditionalUE. In some cases, the recipient of the measurement data from a sensordevice may be interested in just the measurement data (and possibly alocation of the corresponding sensor device), but may not be interestedin the identity of the sensor device itself. In addition, in someexample scenarios, a sudden change in condition within an environmentmay cause a relatively large number of sensor devices in the environmentto simultaneously report their measurement data. Such simultaneousreporting by a relatively large number of sensor devices is referred toas a reporting storm, and may overwhelm a wireless access network.

In contrast, the communication and usage model of traditional UEsassumes relatively long-lived communication sessions that involve theexchange of relatively large amounts of data between the UEs. Using thecommunication and usage model for traditional UEs to supportcommunications of sensor devices may be inefficient and can lead tooverloading of a wireless access network.

If a sensor device operates according to traditional procedures used forUE communications, the following may be employed. The sensor devicesends a random access request to a wireless access network and receivesa subsequent grant for uplink transmission resources. A dedicatedsignaling radio bearer can then be established, and a sensor device thenidentifies itself to the wireless access network. The sensor device thenperforms an authentication procedure with the wireless access network,and a dedicated data radio bearer is then established. The data of thesensor device can then be transmitted over the dedicated data radiobearer. Upon completion, the dedicated data radio bearer can bereleased, and the dedicated signaling radio bearer can be released. Theforegoing process involves a relatively large signaling overhead,results in relatively large battery consumption, and is associated withincreased latency in obtaining radio communication resources to allowthe sensor device to perform communications. Additionally, when appliedto sensor devices, the foregoing process involves inefficient use ofradio resources, and if there are a relatively large number of sensordevices that are reporting simultaneously (a reporting storm), thewireless access network can become overwhelmed by the reporting storm.

In accordance with some implementations, to achieve more efficientcommunications in a wireless access network by sensor devices, trafficdata that is to be communicated by a sensor device can be encoded into acollection of codes that are then transmitted in random access resourcesof the wireless access network. Such a procedure is associated withreduced signaling overhead and more efficient use of radio resources ofthe wireless access network.

In the ensuing discussion, reference is made to communicating trafficdata of a sensor device. More generally, the traffic data of anyelectronic device (including a UE, sensor device, or other type ofdevice) can be communicated in random access resources according to someimplementations. Traffic data of an electronic device refers to datathat is to be communicated by the electronic device to anotherdevice—traffic data differs from any signaling data that is communicatedbetween an electronic device and a wireless access network node toobtain access of wireless resources of the wireless access network node.Traffic data can refer to user data, data generated by a softwareapplication, data measured by a sensor device, or any data that is to beconsumed by a recipient of the data.

A random access resource refers to a resource of a wireless accessnetwork that is traditionally used by an electronic device to initiateaccess to the wireless access network. Such access can be part of acontention-based random access procedure in which the electronic devicecan use the random access resource to perform a random access attemptwith the wireless access network. According to the Long-Term Evolution(LTE) wireless access technology, a random access resource includes aresource of a Physical Random Access Channel (PRACH). A PRACH can besemi-statically allocated by a wireless access network node in eachframe or in each of certain frames (e.g. even-numbered frames). An LTEframe is a data container having a predefined structure. For example, anLTE frame can include LTE subframes, and each subframe has a predefinedtime length. According to LTE, for example, a PRACH occupies sixresource blocks (RBs) in the frequency domain and two slots in the timedomain. In other examples, a random access resource can have otherpredefined formats.

Within each PRACH, the wireless access network node can configure acertain number of orthogonal codes for use in contention-based randomaccess attempts. These orthogonal codes can be Zadoff-Chu orthogonalcodes, which are also referred to as preambles. An orthogonal code isspread over the frequency spectrum of a given radio channel. Multipleorthogonal codes transmitted by multiple electronic devices can bedetected by a wireless access network node. Different orthogonal codestransmitted simultaneously do not interfere with each other, so thatthey can be successfully decoded by the wireless access network node.

LTE is defined by standards provided by the Third Generation PartnershipProject (3GPP). The LTE standards are also referred to as the EvolvedUniversal Terrestrial Radio Access (E-UTRA) standards. In an LTEwireless access network, a wireless access network node is an enhancedNode NB (eNB), which provides base station and base station controllerfunctionalities. Although the ensuing discussion refers to LTEcommunications, it is noted that techniques or mechanisms according tosome implementations can also be applied with other wireless accesstechnologies. More generally, instead of referring to eNBs that are usedin LTE wireless access networks, the ensuing discussion refers towireless access network nodes. A wireless access network node is a nodein a wireless access network that is accessed by an electronic device toperform wireless communications. In addition to an eNB, a wirelessaccess network node can alternatively refer to any of the following: abase station, a nodeB, a wireless local area network/metropolitan areanetwork access point, radio network controller, or any other wirelessaccess controller.

In the ensuing discussion, reference is made to more generic terms thatare applicable for various different wireless access technologies,including “radio resource,” “transmission opportunity,” “orthogonalcode” (or more simply “code”), and “random access resources.” If appliedto LTE, these terms can be mapped to corresponding LTE terms as follows:

-   -   radio resource→resource block (RB);    -   transmission opportunity→Physical Random Access Channel (PRACH)        allocation;    -   orthogonal code or code→PRACH preamble;    -   random access resources→one or more preambles within a PRACH        allocation.

In an LTE contention-based random access procedure, a UE randomlyselects one of the multiple preambles to initiate an access. Theselected preamble is transmitted in a PRACH resource. Upon detecting thepreamble, the wireless access network node sends messaging to the UE,which continues further exchanges of messaging with the wireless accessnetwork node that ultimately can result in access being granted to theUE to perform data communications.

In accordance with some implementations, instead of using a randomaccess resource to initiate a random access procedure in which awireless access network node ultimately grants access of radio resourcesto the sensor device to communicate the sensor device's traffic data,the random access resources can themselves be used for carrying thetraffic data of the sensor device. In alternative implementations,instead of using random access resources, other types of sharedtransmission resources can be used (discussed further below) forcarrying traffic data of the sensor device.

FIG. 1 is a schematic diagram of an example arrangement that includessensor devices 102 and UEs 104. The sensor devices 102 and UEs 104 areable to wirelessly communicate with a wireless access network 106, whichincludes wireless access network nodes 108 that support respectivecoverage areas.

The wireless access network nodes 108 are connected to core networknode(s) 110, through which communications are performed with a datanetwork 112 (e.g. Internet, local area network, etc.).

FIG. 2A is a flow diagram of a process of a sensor device 102, inaccordance with some implementations. The sensor device 102 encodes (at202) traffic data that is to be transmitted. The encoding can includedividing the traffic data into multiple chunks, and applying an encodingfunction to each of the chunks to produce a respective code. The sensordevice 102 then wirelessly sends (at 204) the corresponding codes inrespective random access resources, where the codes collectively providean encoded representation of the traffic data. The codes are sent to awireless access network node 108.

FIG. 2B is a flow diagram of a process of a wireless access network node108 according to some implementations. The wireless access network node108 wirelessly receives (at 210) in random access resources a collectionof codes from a sensor device 102. The wireless access network node 108then decodes (at 212) the collection of codes to produce a decodedversion of the traffic data represented by the collection of codes.After decoding, the wireless access network node 108 can send thedecoded traffic data to another node for forwarding the decoded trafficdata to the targeted recipient of the traffic data. Alternatively, thewireless access network node 108 can use the decoded traffic data toperform an operation.

In accordance with further implementations, one or more of the followingtechniques can also be used for enhanced efficiency or flexibility incommunicating traffic data from sensor devices to wireless accessnetwork nodes:

-   -   Configure multiple sensor devices (such as sensor devices within        a given group) to map a particular traffic data value to the        same sequence of codes so that the wireless access network node        decodes and processes just one transmitted sequence of codes        rather than multiple transmitted sequences of codes when the        same traffic data value is being reported by the multiple sensor        devices.    -   Configure different groups of sensor devices to use different        mappings of data values to codes, which allows the wireless        access network node to identify the group that a sensor device        belongs to based on the codes received. For example, a first        group of sensor devices is configured to use a first set of        codes, a second group of sensor devices is configured to use a        second set of codes, and so forth. Thus, if the wireless access        network node receives a sequence of codes that is from the first        set, then the wireless access network node can detect that the        sensor device that sent the sequence belongs to the first group.    -   Assign transmission opportunities to different groups of sensor        devices at different times to meet the reporting latency        specifications associated with each group. For example, a first        group of sensor devices may be assigned a lower latency        specification (and thus should be given the ability to report        traffic data with reduced latency) than a second group of sensor        devices. As a result, transmission opportunities assigned to the        first group of sensor devices can be such that a sensor device        of the first group would have greater opportunity to send its        traffic data as compared to a sensor device of the second group.    -   Assign subsequent transmission opportunities only to sequences        of codes whose data values received thus far meet a specified        criterion (or criteria). In other words, upon receiving a first        code of a sequence from a sensor device in a first transmission        opportunity, the wireless access network node assigns the next        transmission opportunity to the sensor device for transmitting a        second code of the sequence only if the first code meets a        specified criterion (or criteria).    -   Assign subsequent transmission opportunities to different        sequences of codes at different times to keep radio resources        consumed by sensor traffic data within a specified bound. For        example, if the wireless access network node detects that there        is excessive sensor traffic data being sent by multiple sensor        devices, the wireless access network node can spread apart the        transmission opportunities for subsequence transmissions of        codes of the sequences to ensure that at any given time, the        amount of sensor traffic data does not exceed the specified        bound.    -   Assign subsequent transmission opportunities to different        sequences of codes at different times to allow communication of        sensor traffic data values according to their specified        importance. For example, the traffic data of a first sensor        device may be considered to be more important that the traffic        data of a second sensor device. As a result, the first sensor        device would be given greater opportunity to transmit its        traffic data than the second sensor device.    -   Identify a sequence number of the next code to be transmitted        from sequences of codes when assigning a subsequent transmission        opportunity to select the next traffic data field to be        transmitted. This can allow the wireless access network node to        specify that codes of a sequence be sent out-of-order.    -   Identify a sequence number of the next code to be transmitted        from sequences of codes when assigning a subsequent transmission        opportunity to request retransmission of corrupted information.        For example, if a particular code in a sequence was not        successfully received by a wireless access network node, then        the wireless access network node can identify, to the sensor        device, the sequence number of the code to re-transmit.        Traffic Data Encoding

At a sensor device 102, the traffic data that is to be transmitted bythe sensor device is encoded into a collection of codes (e.g. collectionof LTE random access preambles). As shown in FIG. 3, traffic data 302 tobe transmitted is divided into chunks, where each chunk is mapped to arespective code in the collection of codes. In the example of FIG. 3,the traffic data 302 is divided into three chunks c₁, c₂, c₃.

In the example of FIG. 3, the traffic data 302 is 16 bits long (haslength L of 16 bits). Each of the three chunks c₁, c₂, c₃ is 6 bits long(each chunk has length b of 6 bits). Note that the third chunk (c₃) ispadded with two extension bits at the end (represented as xx, where xxcan be any specified value). The number (n) of chunks into which thetraffic data 302 is divided is based on L and b—more specifically,n=[L/b] (the number of chunks is equal to the next larger integer of thevalue L/b).

Chunk c₁ is mapped to a first code 304 (z₂₇), chunk c₂ is mapped to asecond code 306 (z₃₇), and chunk c₃ is mapped to code 308 (z₃₈). Thethree codes 304, 306, and 308 are selected from 64 total possible codes(z₀ to z₆₃), as shown in FIG. 3, based on the specific encoding that isperformed on each chunk. More specifically, an encoding function can beapplied to the content of each chunk, and this encoding functionproduces an output that corresponds to one of the 64 codes. The numberof possible codes (K) to which a chunk can be mapped depends on thelength of the corresponding chunk.

Although specific values are specified for L and b in the example ofFIG. 3, it is noted that in other examples, traffic data can have otherlengths and chunks can have other lengths. Moreover, different instancesof traffic data can have different lengths, and chunks can have variablelengths.

As further depicted in FIG. 3, the codes 304, 306, and 308 are output ina sequence 310 of codes, S=(z₂₇, z₃₇, z₃₈). The codes of the sequence310 are carried in respective random access resources to the wirelessaccess network node 108 of FIG. 1.

Each code in the sequence is transmitted by the sensor device 102 in arandom access resource within a transmission opportunity scheduled bythe wireless access network node 108 that serves the sensor device.

In some implementations, the wireless access network node 108 can assigna first set of codes for use in signaling a random access attempt (astraditionally used by UEs 104), and a second, different set of codes foruse in carrying traffic data from sensor devices 102. Thus, dependingupon whether codes received by the wireless access network node 108 arepart of the first set or second set, the wireless access network node108 can determine whether the received codes are part of acontention-based random access procedure, or the received codes are usedto convey traffic data. More specifically, if a sequence of codesreceived by the wireless access network node is from the first set ofcodes, then the wireless access network node detects the sequence as arandom access attempt. On the other hand, if a sequence of codesreceived by the wireless access network node is from the second set,then the wireless access network node detects the second sequence ascontaining traffic data.

When codes are used to signal a random access attempt, the transmissionof the same code by more than one UE in a given transmission opportunityis treated as a random access collision. In this scenario, adisambiguation procedure is performed to identify the UEs that wereattempting to access the network. However, when codes are used to conveytraffic data, the transmission of the same code by more than one sensordevice in a given transmission opportunity is not treated as acollision; rather, it is treated as a condition in which multiple sensordevices are transmitting the same data portion.

Different sensor devices may send the same traffic data, or they maysend different traffic data, or they may send traffic data that have acommon portion and different portions. From the perspective of thewireless access network node, this is equivalent to different sensordevices sending the same sequence of codes, or sending completelydifferent sequences of codes, or sending a sub-sequence of common codesfollowed by sub-sequences of different codes. The wireless accessnetworks node can decode the received codes accordingly.

In the present discussion, reference is made to sending codesrepresenting traffic data in random access resources in correspondingtransmission opportunities. In other implementations, the codesrepresenting traffic data can be sent in other types of sharedtransmission resources in corresponding time intervals. A sharedtransmission resource refers to a resource that can be used by multiplesensor devices to send code(s) representing respective portion(s) oftraffic data to a wireless access network node. Within a given timeinterval, if at least two sensor devices are sending a common code(which corresponds to a common chunk to be sent by each of the at leasttwo sensor devices), then the common code can be sent by the at leasttwo sensor devices in the same shared transmission resource in the giventime interval.

Note that the multiple sensor devices are to transmit their respectivesequences of codes, where the sequences may share at least one commoncode if the respective traffic data to be transmitted by the multiplesensor devices share a common chunk. This common code sent in the sameshared transmission resource in the same time interval is not treated asa collision by the wireless access network node, but rather is treatedas a condition in which multiple sensor devices are transmitting thesame data portion. After receiving codes in the shared transmissionresources in a series of time intervals, the wireless access networknode can decode the received codes to reproduce respective decodedversions of distinct traffic data transmitted by the multiple sensordevices. Note that if all of the sensor devices transmitted the sametraffic data, then the wireless access network node would decode justone traffic data.

The techniques or mechanisms discussed herein relating to communicatingcodes of traffic data in random access resources can also be applied tocommunicating codes of traffic data in other types of sharedtransmission resources.

Further details of traffic data encoding are discussed below.

The traffic data to be sent by a sensor device D can be treated as anopaque bit string of length L. In some implementations, the length L isfixed and known to both a sensor device and the wireless access networknode for a given group (or type) of sensor devices. In one variant, thetraffic data sent by a sensor device D is always the same length and isequal to L. In another variant, the traffic data sent by a sensor deviceD may be of varying length, in which case L represents the fixed size ofa container (e.g. packet data unit or PDU) for the traffic data andconstrains the maximum length of the data bit string that is actuallytransmitted by the sensor device. In some examples, the actual length ofthe transmitted data is incorporated with the data bit stringtransmitted by a sensor device. In other implementations, the end of thedata bit string is encoded into the data bit string transmitted by asensor device.

The value of L may be determined in a number of different ways, some ofwhich are dependent on the capabilities of the sensor device. Forexample, in some implementations, sensor devices may have relatively lowprocessing power to reduce their cost. In these instances, the length Lmay be fixed for all sensor devices of a certain group; e.g. one type ofsensor device may send 8 bits of data, while another type of sensordevice may send 12 bits of data. The length L for a particular group ofsensors is provisioned at the wireless access network node. In otherimplementations, sensor devices may be able to signal their capabilities(including the value of L) to the wireless access network node during anassociation or initialization phase that precedes communications oftraffic data in random access resources.

Using any of various mechanisms, the value of L can be known a priori byboth the wireless access network node and the sensor device.

As noted above, the data bit string of length L is partitioned into nchunks of equal length with b bits per chunk such that n=[L/b]—the lastchunk of bits is extended or padded to ensure there are b bits in thelast chunk. In some examples, the value of b (and, hence, of n) can befixed and is known a priori to both the wireless access network node andthe sensor device. This information may be explicitly configured by thewireless access network node through a broadcast or other signallingmessage, or the information may be preconfigured into the sensordevices. Note that the value of b is dependent on the number K oforthogonal codes made available by the wireless access network node ineach transmission opportunity, K=2^(b). In some implementations, thewireless access network node can send signalling to a sensor device toconfigure a number of available orthogonal codes to use for eachtransmission opportunity.

An encoding function E is applied to each chunk, c_(i) (1≦i≦n), toselect one of the K=2^(b) orthogonal codes from the set Z={z₀, . . . ,z_(K−1)}, in other words, E(c_(i))εZ. The sequence of codes to betransmitted is S=[k₁, . . . , k_(n)]=[z_(E(c) ₁ ₎, . . . , z_(E(c) _(n)₎].

The foregoing describes implementations where the encoding of each chunkinvolves selecting an orthogonal code from a fixed number of possibleorthogonal codes.

In alternative implementations, the wireless access network node may usevarious numbers of orthogonal codes for different chunks of trafficdata. Such strategy can configure a reduced number of random accessresources (reduced number of orthogonal codes) for the firsttransmission opportunity and to dynamically allocate a larger number ofrandom access resources (larger number of orthogonal codes) for asubsequent transmission opportunity once the number of transmitted codesis known to the wireless access network node.

In such implementations, the traffic data to be sent by a sensor deviceD is treated as an opaque bit string of length L that is partitionedinto m chunks of unequal length, with b_(i) bits in chunk i (i=1 . . .m); the last chunk of bits can be extended or padded to ensure there areb_(m) bits in the last chunk. For example, a data bit string of lengthL=16 may be partitioned into three chunks (m=3) with the length of thefirst chunk b₁=4, the length of the second chunk b₂=8, and the length ofthe third chunk b₃=4. Note that the value of b_(i) is dependent on thenumber of orthogonal codes K_(i) made available by the wireless accessnetwork node in transmission opportunity t_(i), i.e. K_(i)=2^(b) ^(i) .

In some examples, the number of chunks (m) is fixed and the length ofeach chunk (b_(i)) is known a priori to both the wireless access networknode and the sensor devices for a given group (or type) of sensordevices. This information may be explicitly configured by the wirelessaccess network node through a broadcast or other signalling message, orit may be preconfigured into the sensor devices.

In other examples, the number of chunks (m) may be variable, based onthe number of orthogonal codes K_(i) made available by the wirelessaccess network node in each transmission opportunity t_(i). The numberof orthogonal codes K_(i) (or, equivalently, the length of the chunkb_(i)) may be signalled to the sensor devices in the allocation ofrandom access resources by the wireless access network node in eachtransmission opportunity. For example, with LTE, the Physical DownlinkControl Channel (PDCCH) Downlink Control Information (DCI) may beextended to dynamically allocate random access resources to sensordevices. In some examples, an entire PRACH with 64 preambles may bededicated to sensor device traffic data; in other examples, a number ofpreambles (≦64) may be allocated to sensor device traffic data within anexisting PRACH allocation.

A function E is applied to each chunk, c_(i) (1≦i≦m), to select one ofthe K_(i)=2^(b) ^(i) orthogonal codes from the set Z_(i)={z₀, . . . ,z_(K) _(i) ⁻¹}, i.e. E(c_(i)) ε Z_(i). The sequence of codes to betransmitted is therefore, S=[k₁, . . . , k_(m)]=[z_(E(c) ₁ ₎, . . . ,z_(E(c) _(m) ₎].

Simple Encoding Function

In some implementations, a simple encoding function E (c_(i))→z_(v) _(i)can be applied, where the binary value v_(i) of chunk c_(i) selectsorthogonal code z_(v) _(i) to transmit in opportunity t_(i) of thesequence. In other implementations, E may incorporate other parametersin addition to the binary value of c_(i).

An example of the simple encoding function is illustrated in FIG. 3. Thetraffic data 302 to send is the data bit string {0110 1110 0101 1001}.Organizing the 16 bits of data into n=┌16/6┐=3 equal-length chunksresults in:

-   -   c₁=011011,    -   c₂=100101,    -   c₃=1001xx.

In an example, the extension bits xx in the third chunk can be set to analternating pattern of 1s and 0s, resulting in c₃=100110.

In the foregoing example, the binary values v₁, v₂, v₃ of the respectivechunks c₁, c₂, c₃ are 27, 37, 38, respectively. Using function E(c_(i))→z_(v) _(i) with the set of preambles Z={z₀, . . . , z₆₃}, thesequence of codes used to encode the traffic data 302 is S=[k₁, k₂,k₃]=[z₂₇, z₃₇, z₃₈].

Grouping of Sensor Devices and Group Encoding Function

In alternative implementations, different encoding functions can be usedfor respective different groups of sensor devices.

In some examples, sensor devices can be organized into different groups.The sensor devices in a system may be organized into J (J≧1) groups suchthat all of the sensor devices in group g_(i) (jεJ) can have, forexample, one or more of the following in common:

-   -   are physically located within a particular geographical area;    -   are owned by a particular entity;    -   report the same type of information (e.g. temperature, hazardous        gas levels, bridge girder strain);    -   share some device characteristic (e.g. 8-bit traffic data versus        16-bit traffic data); or    -   share a data encryption key.

In some implementations, an initial transmission opportunity t₁ ^(g)^(j) may be assigned to the sensor devices of group g_(j) so that a codereceived by the wireless access network node in t₁ ^(g) ^(j) can beassociated with sensor group g_(j).

In further implementations, an identifier for the sensor group g_(j)associated with a sensor device may be included in the data bit stringtransmitted by that sensor device.

An encoding function E may be different for each sensor group g_(j). Forexample, different groups may be assigned different sets of orthogonalcodes such that, for group g_(j), Z^(g) ^(j) ={z₀ ^(j), . . . , z_(M−1)^(j)}. Therefore, when the wireless access network node receives a codez_(m) ^(j), the wireless access network node can determine that theinformation was transmitted by a sensor device within the sensor groupg_(j).

FIG. 4 shows an example of different encodings applied for sensordevices of two different groups g₁ and g₃. A sensor device in group g₁is to send traffic data 402, and a sensor device in group g₃ is to sendtraffic data 404. Both traffic data 402 and 404 are the same 8-bit bitstring {0101 1011}.

Sensor device D_(x) ¹ is a member of device group g₁ while sensor deviceD_(y) ³ is a member of device group g₃. Each device group has beenassigned 8 (2³) orthogonal codes in each transmission opportunity suchthat the chunk length is b=3. The 8 orthogonal codes for each group maybe selected from the 64 available orthogonal codes. In an example,device group g₁ has been assigned the set of orthogonal codes Z^(g) ¹={z₀, . . . , z₇}, while device group g₃ has been assigned the set oforthogonal codes Z^(g) ³ ={z₂₄, . . . , z₃₁}.

Note that although this example shows the allocation of orthogonal codesin a contiguous block, other examples may allocate non-contiguous setsof codes and define an appropriate mapping function to select theorthogonal code corresponding to a given chunk of data. For example,E(c_(i))→Z={z₁, z₇, z₁₁, z₁₇, z₂₃, z₃₁, z₄₃, z₅₉}.

Each traffic data 402 or 404 is divided into the following three chunks:

-   -   c₁=010,    -   c₂=110,    -   c₃=11x,        where x is an extension bit to ensure that there are 3 bits in        the final chunk.

In an example, the extension bit can be set to 1, resulting in c₃=111.

Using encoding function E (c_(i))→z_(v) _(i) with the set of codes Z^(g)¹ ={z₀, . . . , z₇}, the sequence of codes used to encode the data fromdevice D_(x) ¹ is S¹=[k₁ ¹, k₂ ¹, k₃ ¹]=[z₀, z₆, z₇].

Similarly, using the set of codes Z^(g) ³ ={z₂₄, . . . , z₃₁}, thesequence of codes used to encode the data from device D_(y) ³ is S³=[k₁³, k₂ ³, k₃ ³]=[z₂₆, z₃₀, z₃₁].

As a result, the wireless access network node is able to determine thatthe same traffic data value has been reported by one or more sensordevices in each of two distinct sensor groups.

Traffic Data Transmission

As noted above, traffic data is sent from a sensor device D to awireless access network node as a sequence S_(D) of orthogonal codes [k₁^(D) . . . k_(n) ^(D)]. The sequence S_(D) is sent iteratively with thesensor device transmitting code k_(i) ^(D) in a transmission opportunityt_(i) designated by the wireless access network node. In each iterationi, the code k_(i) ^(D) in the sequence S_(D) may also be transmitted byanother sensor device in transmission opportunity t_(i), in other words,for two transmitting sensor devices D1 and D2, it is possible that k_(i)^(D1)=k_(i) ^(D2).

For enhanced efficiency, the only random access resources initiallyallocated by the wireless access network node to sensor devices are theuplink resources for the first transmission opportunity t₁, allowing oneor more sensor devices (with traffic data to report) to transmit thefirst code (k₁) in their respective sequence. The timing of thistransmission opportunity is based on the latency specificationassociated with traffic data from the sensor devices allowed to transmitin that transmission opportunity.

Since data transmissions from sensor devices may be intermittent and mayoccur at unpredictable times, there is no guarantee that any sensordevice will have data to transmit in that transmission opportunity. As aresult, there may be some probability that the transmission opportunitymay not be used by any sensor device and that the radio resourcesallocated for a given transmission opportunity t_(i) may be wasted.

To reduce the number of potentially wasted radio resources, the wirelessaccess network node dynamically allocates radio resources for eachsubsequent iteration t_(i+1) only in response to the codes received inthe previous iteration t_(i). This allows the wireless access networknode to allocate subsequent resources only in response to informationactually transmitted by one or more sensor devices.

FIG. 5 is a message flow diagram of messaging exchanged between a sensordevice 102 and a wireless access network node 108 for communicatingsensor traffic data using codes in respective random access resources.It is assumed in the example of FIG. 5 that sensor devices are dividedinto multiple groups—in other examples, grouping is not performed.

The wireless access network node 108 sends (at 502) an uplink allocation(for assigning uplink resources) to the sensor device D (102) (and allof the other sensor devices in group g_(i)). The uplink grant provides atransmission opportunity at time t₁ ^(g) ^(j) =T₁.

At time T₁, the sensor device D uses the assigned uplink resources totransmit (at 504) the first code k₁=z₂₇ (for example) in its sequence S.At least another sensor device in the group g_(i) may also send itsrespective first code.

For each code z_(r) _(i) detected by the wireless access network node108 at time T₁, the wireless access network node 108 assigns uplinkresources in a subsequent transmission opportunity T₂ for thetransmission of the next code k₂ in the sensor devices' sequence, i.e.no uplink resources are assigned in T₂ for codes that are not detectedat T₁. The wireless access network node 108 sends (at 506) anotheruplink allocation (for code z₂₇) to the sensor device D. The wirelessaccess network node 108 also sends an uplink allocation for any otherdistinct code (received from another sensor device) detected by thewireless access network node 108.

The sensor device D detects the uplink allocation for z₂₇ and transmits(at 508) its second code k₂=z₃₇ in the assigned resources at time T₂.Any other sensor device D would also send its respective second codeusing its respective uplink allocation at time T₂.

Again, for each code z_(r) ₂ detected at time T₂, the wireless accessnetwork node 108 assigns uplink resources in a subsequent transmissionopportunity T₃ for the transmission of the next code k₃ in the sensordevices' sequences, i.e. no uplink resources are assigned in T₃ forcodes that are not detected at time T₂. The wireless access network node108 sends (at 510) another uplink allocation (for code z₃₇) to thesensor device D. The wireless access network node 108 also sends anuplink allocation for any other distinct code (received from anothersensor device) detected by the wireless access network node 108.

The sensor device D detects the uplink allocation for z₃₇ and transmits(at 512) its third and final code k₃=z₃₈ in the assigned resources attime T₃. Any other sensor device D would also send its respective secondcode using its respective uplink allocation at time T₃.

Note that the number of uplink resources assigned at a given timeT_(i+1) is not based on the number of sensor devices that transmitted attime T_(i); rather, the number of uplink resources assigned at timeT_(i+1) is based on the number of unique codes received by the wirelessaccess network node 108 at time T_(i) in respective random accessresources.

To reduce the number of uplink resources used to convey traffic datafrom a population of sensor devices, data to be transmitted from thesensor devices should be organized to enhance the probability thatmultiple sensor devices will send the same data chunk value (by use ofthe same code) in an allocated uplink resource. For example, when datais sent with the most significant bit first, the sensor devices can beconfigured to send the common codes corresponding to the mostsignificant bits in the same random access resources, followed by thesending of distinct codes corresponding to the different leastsignificant bits.

FIG. 6 depicts a specific example in which there are four sensor devicesD1, D2, D3, and D4 that are to transmit respective traffic data usingcodes in respective random access resources. FIG. 6 assumes an LTEimplementation in which the random access resources are PRACH resources.

In the FIG. 6 example, it is assumed that the wireless access networknode 108 has configured the system such that eight orthogonal codes(preambles) {0, 1, . . . , 71} are available in each PRACH, and that thetraffic data in each sensor device has been divided into three chunks(n=3). The four sensor devices have the following sequences of codes totransmit:

-   -   D1=[0,1,5],    -   D2=[2,1,1],    -   D3=[2,4,5],    -   D4=[2,4,3].

An initial PRACH resource, PRACH A, has also been semi-staticallyallocated by the wireless access network node 108, and the configurationof PRACH A has been communicated to all sensor devices D1-D4 (at 502 inFIG. 5, for example) using a System Information Block (SIB) or RadioResource Control (RRC) signalling.

At time T1, the four sensor devices each transmit the first code intheir sequence using the resources of PRACH A, i.e. sensor device D1transmits code 0, while sensor devices D2, D3, and D4 all transmit code2. The hashed blocks in PRACH A indicate which of the codes in {0, 1, .. . , 7} were transmitted in PRACH A by the four sensor devices.

The wireless access network node 108 detects the two distincttransmitted codes 0 and 2 and dynamically allocates an additional PRACHresource for each detected distinct code. Physical Downlink ControlChannel (PDCCH) Downlink Control Information (DCI) can be used to signalthe allocation of PRACH B1 for sensor device(s) (i.e. D1) thattransmitted code 0, and the allocation of PRACH B2 for all sensordevices (i.e. D2, D3, and D4) that transmitted code 2. There is onePDDCH DCI per allocated PRACH resource. PDDCH DCIs are examples ofuplink allocations transmitted by the wireless access node 108 at 506 inFIG. 5.

Each of the sensor devices decodes the DCI corresponding to its firsttransmitted code. At time 72, the four sensor devices then transmit thesecond code in their sequence using the respective assigned PRACH, i.e.the sensor device D1 transmits code 1 in PRACH B1, the sensor device D2transmits code 1 in PRACH B2, and the sensor devices D3 and D4 bothtransmit code 4 in PRACH B2.

The wireless access network node 108 detects the one transmitted code 1in PRACH B1 and the two transmitted codes 1 and 4 in PRACH B2, anddynamically allocates an additional PRACH resource for each detectedcode. PDCCH DCIs (sent at 510 in FIG. 5, for example) are used to signalthe allocation of PRACH C1 for all sensor devices (i.e. D1) thattransmitted code 1 in PRACH B1, the allocation of PRACH C2 for allsensor devices (i.e. D2) that transmitted code 1 in PRACH B2, and theallocation of PRACH C3 for all sensor devices (i.e. D3 and D4) thattransmitted code 4 in PRACH B2.

Each of the sensor devices decodes the DCI corresponding to its secondtransmitted code and then, at time T3, the four sensor devices transmitthe third code in their sequence using the assigned PRACH resources,i.e. the sensor device D1 transmits code 5 in PRACH C1, the sensordevice D2 transmits code 1 in PRACH C2, the sensor device D3 transmitscode 5 in PRACH C3, and the sensor device D4 transmits code 3 in PRACHC3.

The wireless access network node 108 detects the four distinct codestransmitted in the third iteration thus detects the conclusion of thetransmissions of respective traffic data by the four sensor devices.

Duplicate Traffic Data Filtering

Various management tasks can be performed by a wireless access networknode 108 to improve efficiency in transmissions of traffic data bysensor devices. In some implementations, a wireless access network node108 may configure all sensor devices in a group to use the same mappingfunction E(c). As noted above, since the data value reported by a sensordevice may not be unique, multiple sensor devices in a group may, at anygiven time, report the same chunk value and, in doing so, will transmitthe same code. This provides an inherent and effective traffic datafilter so that a wireless access network node only has to handle uniquechunk values transmitted by the sensor group.

Such traffic data filtering can reduce resource usage. Since uplinkresources are assigned based on the codes Z_(r) _(i) received initeration i, fewer distinct codes result in assignment of fewer uplinkresources to sensor devices. Since resource assignments are based on thenumber of received codes and not on the number of sensor devices, thisalso reduces the number of downlink control channel resources fortransmitting uplink grants from the wireless access network node 108 tothe sensor devices.

Traffic data filtering can also mitigate effects of reporting storms. Ifa single event results in the near-simultaneous transmission of the sameinformation from numerous sensor devices, the number of distinct reportsis significantly reduced thereby such that scheduling overhead andaccess link congestion can be reduced.

Traffic data filtering also reduces backend processing load. With areduction in the number of distinct reports by sensor devices, theamount of information processing performed by backend servers (includingthe wireless access network nodes 108) is also reduced.

Truncating Data Values

In some implementations, the first bit of a data bit stringcorresponding to traffic data can represent the most significant bit ofthe traffic data so that the most significant bits of the data aretransmitted first. In some implementations, a wireless access networknode 108 can control the precision of the data values being reported byprematurely terminating the sequence of transmission opportunities(before the entirety of the traffic data is sent). This has the effectof truncating the traffic data.

For example, a sensor device may be equipped to provide very accuratemeasurements that are represented in a data bit string of length L andreported in n chunks of b bits per chunk, where b<<L. In some instances,a wireless access network node 108 may wish to receive all L bits (nchunks) of the traffic data, but in other instances the wireless accessnetwork node 108 may decide to stop receiving the least significant bitsof information after receiving only m (m<n) chunks (i.e. m*b bits). Thewireless access network node 108 can perform the truncation by decidingto not send any further grants of uplink resources to a sensor devicefor further chunk(s) of the traffic data, even though not all chunk(s)of the traffic data has or have been sent by the sensor device.

Truncating reported traffic data may be performed to (1) dynamicallycontrol the precision of reported traffic data values; (2) reduce radioresource usage when reported traffic data values differ in only the l(l=L−(m*b)) least significant bits; (3) reduce radio resource usage byignoring data values that fall outside a range that is of interest; or(4) reduce system load during reporting storms.

Sampling Traffic Data Values

In some implementations, a wireless access network node 108 mayselectively sample the traffic data transmitted by a group of sensordevices to reduce the volume of sensor traffic data or to discardtraffic data values that are not of interest. For example, afterdecoding the codes k_(i−1) received in the transmission opportunity att_(i−1), the wireless access network node 108 may only allocatesubsequent transmission opportunities to those codes k_(i) correspondingto:

-   -   the j largest k_(i−1) values (j≧1);    -   the i smallest k_(i−1) values (i≧1);    -   k_(i−1) values within the range V_(LOWER) and V_(UPPER);    -   k_(i−1) values outside a standard deviation of the previously        reported code values;    -   k_(i−1) values outside the normal reporting range of a sensor        device or group of sensor devices; or    -   a specific subset of reporting sensor devices.

The foregoing are examples of criteria used by the wireless accessnetwork node 108 to determine whether or not a transmission opportunity(and the respective uplink resources) are to be assigned in response toa received code from a sensor device. The wireless access network node108 can use any one or some combination of the foregoing criteria.

An example of sampling traffic data values is illustrated in FIG. 7, inwhich the thicker lines show the sampled sequence paths (i.e. pathscorresponding to sequences from sensor devices that are selected fortransmission by the wireless access network node 108). In this example,transmission of the data bit string of length L from the sensor devicesis performed in three iterations (n=3).

In iteration 1 (the first transmission opportunity), the wireless accessnetwork node 108 detects six codes, z₁, z₂, z₃, z₄, z₅ and z₆, in PRACHA, where the six codes represent the initial codes in the sequences tobe transmitted by six or more sensor devices.

Based on the corresponding values of the received codes in iteration 1,the wireless access network node 108 chooses to assign subsequenttransmission resources (PRACH B1, PRACH B2, PRACH B3) to three of thesequences, i.e. those associated with codes z₂, z₅ and z₆. Notransmission resources are assigned to the other three sequences, i.e.associated with codes z₁, z₃, and z₄ (represented by dashed boxes) initeration 1.

In iteration 2, the wireless access network node 108 receives codesz_(2.1), z_(2.2) and z_(2.3) in PRACH B1, codes z_(5.1) and z_(5.2) inPRACH B2, and code z_(6.1) in PRACH B3. Based on the correspondingvalues of the received codes, the wireless access network node 108chooses to assign subsequent transmission resources (PRACH C1, PRACH C2,PRACH C3, PRACH C4) to four of the sequences, i.e. those associated withcodes z_(2.1), z_(2.3), z_(5.1) and z_(6.1). However, no transmissionresources are assigned to the other two sequences, i.e. those associatedwith codes z_(2.2) and z_(5.2) (represented by dashed boxes in iteration2).

In iteration 3, the wireless access network node 108 receives codesrepresenting the final values for the selected sequences in theirassigned transmission opportunities, including codes z_(2.1.1) andz_(2.1.2) in PRACH C1, code z_(2.3.1) in PRACH C2, code z_(5.1.1) inPRACH C3 and code z_(6.1.1) in PRACH C4.

In some examples, the sequence paths of FIG. 7 not selected by thewireless access network node 108 for transmission may represent sensortraffic data values that are not of interest to the wireless accessnetwork node 108. For example, such sensor traffic data values may havebeen discarded by the wireless access network node 108 even if received.Alternatively, the unselected transmission paths may correspond totruncated portions of sensor traffic data values. In other examples, thewireless access network node 108 may revisit the sequence paths thatwere not selected in the first set of iterations and retrieve thosepreviously unselected traffic data portions in a subsequent set ofiterations (such as when load balancing is performed, as discussedbelow).

Load Balancing

In some implementations, a wireless access network node 108 may beconfigured with an upper bound on the number of radio resources pertransmission opportunity that may be allocated to sensor traffic data.By selectively scheduling transmission opportunities for subsequentiterations based on received code sequences (discussed above), thewireless access network node 108 can constrain traffic to a subset ofthe received code sequences to meet a target amount of sensor trafficdata to be transmitted at any given time.

For example, in an LTE system, a wireless access network node 108 may beconfigured to limit the number of radio resources (e.g. resource blocks)available for sensor traffic data to x % (x≧0) of the available channelbandwidth in a given frame. If the number of unique codes k_(i) receivedin a PRACH resource at transmission opportunity t_(i) would involveallocation of subsequent PRACH resources that would exceed this x %constraint, the wireless access network node 108 may allocate PRACHresources for a first subset of codes in one frame and for a secondsubset of codes in a subsequent frame, and so on, until all of thesensor devices of interest have had an opportunity to report their data.

For example, after retrieving the sensor data values associated with thefirst three sequences corresponding to the initial codes z₂, z₅ and z₆(as shown in FIG. 7), the wireless access network node 108 may scheduletransmission opportunities for further iterations to obtain theremaining codes for the other three sequences corresponding to theinitial codes z₁, z₃, and z₄, to retrieve the remaining sensor trafficdata values.

FIG. 8 shows iteration 1 (of FIG. 7), in addition to iterations 4 and 5(which occur after iteration 3 of FIG. 7). Following completion ofiteration 3 (in FIG. 7) and reception of the sequences corresponding tothe initial codes z₂, z₅ and z₆ (depicted in FIG. 7), the wirelessaccess network node 108 next assigns transmission resources (PRACH D1,PRACH D2, PRACH D3) to the three remaining sequences, i.e. thoseassociated with codes z₁, z₃, and z₄ in iteration 1.

In iteration 4, the wireless access network node 108 receives codez_(1.1) in PRACH D1, codes z_(3.1) and z_(3.2) in PRACH D2, and codesz_(4.1) and z_(4.2) in PRACH D3. Based on the corresponding values ofthe received codes, the wireless access network node 108 chooses toassign subsequent transmission resources (PRACH E1, PRACH E2, PRACH E3,PRACH E4) to four of the sequences, i.e. those associated with codesz_(1.1), z_(3.1), z_(3.2) and z_(4.2). However, the wireless accessnetwork node 108 does not assign further transmission resources to thesequence associated with code z_(4.1) (represented by a dashed box).

In iteration 5, the wireless access network node 108 receives codesrepresenting the final values for the second set of sequences in theirassigned transmission opportunities: code z_(1.1.1) in PRACH E1, codesz_(3.1.1) and z_(3.1.2) in PRACH E2, code z_(3.2.1) in PRACH E3 andcodes z_(4.2.1) and z_(4.2.2) in PRACH E4.

In further implementations, in addition to load balancing as discussedabove, the scheduling of transmission opportunities may be prioritizedto ensure that the sampled sensor traffic data values are receivedaccording to their specified importance. The wireless access networknode 108 may, for example, allocate transmission opportunities accordingto one or more of the following criteria:

-   -   the j largest k_(i−1) values in transmission opportunity        t_(i−1);    -   the i smallest k_(i−1) values;    -   k_(i−1) values within the range v_(LOWER) and v_(UPPER);    -   k_(i−1) values outside a standard deviation of previously        reported code values;    -   k_(i−1) values outside the normal reporting range of a sensor        device or group of sensor devices; or    -   a specified subset of reporting sensor devices.

In this way, the wireless access network node 108 can trade off thenumber of radio resources allocated to sensor traffic data in any givenframe against the increased latency associated with spreading sensortraffic data over an extended period of time.

Reporting Structured Data

In some implementations, the information reported by a sensor device isstructured so that a data bit string of length L is made up of f (f≧1)fields of respective lengths [L₁, . . . , L_(f)] such that L=L₁+L₂+ . .. L_(f). In some cases, the fields [F₁, . . . , F_(f)] can be reportedin sequence (in other words, according to the sequence of chunks thatmake up the data bit string). In other cases, the wireless accessnetwork node 108 may skip some fields by controlling which chunk is tobe transmitted by a sensor device in the next transmission opportunity.For example, with LTE, the Physical Downlink Control Channel (PDCCH)Downlink Control Information (DCI) may be extended to identify thesequence number (i) of a sequence to be reported in the allocated uplinkresources; this will indicate to the sensor device which chunk (c_(i))and corresponding code (k_(i)) in the sequence the sensor device shouldreport. A sequence is made up of codes indexed by respective sequencenumbers. In another example, the DCI may be extended to identify the bitq, within the L bits of the data bit string (i.e. q selected from therange 1 to L), that will be the first bit of the next chunk transmittedby the sensor device.

For example, as shown in FIG. 9, a sensor device D has 24 bits (L=24) oftraffic data 902 to transmit, where the traffic data 902 includes a databit string {1000 0101 0010 0001 1111 0111}.

A set of codes are used that includes 16 (2⁴) codes in each transmissionopportunity, which means that the chunk length is 4 (b=4).

Organizing the 24 bits of the data bit string into n=[24/4]=6equal-length chunks results in:

-   -   c₁=1000,    -   c₂=0101,    -   c₃=0010,    -   c₄=0001,    -   c₅=1111,    -   c₆=0111.

As a result, the values of the six chunks are as follows:[v ₁ ,v ₂ ,v ₃ ,v ₄ ,v ₅ ,v ₆]=[8,5,2,1,15,7].

Using function E(c_(i))→z_(v) _(i) with the set of codes Z={z₀, . . . ,z₁₅}, the resulting sequence of codes used to encode the data is:S=[k ₁ ,k ₂ ,k ₃ ,k ₄ ,k ₅ ,k ₆ ]=[z ₈ ,z ₅ ,z ₂ ,z ₁ ,z ₁₅ ,z ₇].

In this example, each group of 8 bits can be treated as a structureddata field, F_(d) (d selected from the range 1 to f), so that the databit string is defined as data fields [F₁, F₂, F₃]→[(c₁, c₂), (c₃, c₄),(c₅, c₆)]. As shown in FIG. 9, a sensor device sends the first field F₁in two iterations (at times T₁ and T₂, respectively) corresponding to(c₁, c₂)→(k₁, k₂)→(z₈, z₅).

The wireless access network node 108 then responds with an allocationfor the fifth code in the sequence (k₅) at time T₃, skipping the thirdand fourth codes in the sequence (k₃ and k₄), which effectively skipsdata field F₂.

The sensor device then sends the data field F₃ in two iterations (attimes T₃ and T₄, respectively) corresponding to (c₅, c₆)→(k₅, k₆)→(z₁₅,z₇).

The wireless access network node 108 can later send an allocation forone of the third and fourth codes, which corresponds to the field F₂, tocause the sensor device to send the data field F₂ in two iterations (attimes T₅ and T₆).

Using the foregoing techniques, the wireless access network node 108 cancause the sensor device to send codes out-of-sequence, rather thanin-sequence.

Identifying Sensor Devices

As noted above, in some implementations, a recipient of traffic datafrom a sensor device does not care about the specific identity of thesensor device. In other implementations, identifiers of sensor devicescan be provided.

For example, a sensor device identifier may be appended to the sensortraffic data to form a data bit string to be transmitted. Conceptually,the added bits can be considered a part of the data that is sought bythe wireless access network node 108 and may be similarly requested in asequential manner. This allows the wireless access network node 108 toeither receive both the data and the identifier or, by truncating thedata bit string, to receive only (the most significant bits of) the dataor, by selectively skipping portions of the data (such as depicted inconnection with FIG. 9), to receive the identifier and only the mostsignificant bits of the sensor traffic data.

The sensor device identifier may, for example, include one or more of:

-   -   a unique device identifier;    -   a manufacturer's product identifier;    -   a hardware (version) identifier; or    -   a software (version) identifier.        System Architecture

FIG. 10 is a block diagram of an example arrangement that includes anelectronic device (e.g. sensor device 102) and a wireless access networknode 108 according to some implementations.

The electronic device 102 includes an encoder 1002 that encodes trafficdata 1004 of the electronic device 102 according to someimplementations. The encoded traffic data includes a sequence of codes1005 that are transmitted in respective random access resources over awireless link 1006 to the wireless access network node 108. The encoder1002 is executable on one or multiple processors 1008, which isconnected over a bus 1014 to a storage medium 1010 (that stores thetraffic data 1004) and a wireless interface 1012 to perform wirelesscommunications with the wireless access network node 108. A processorcan include a microprocessor, microcontroller, processor module orsubsystem, programmable integrated circuit, programmable gate array, oranother control or computing device.

The wireless access network node 108 receives the sequence of codes1005. The wireless access network node 108 includes a decoder 1020 todecode the sequence of codes 1005, which produces decoded traffic data1022 (which is a copy of the traffic data 1004 in the electronic device102).

The decoder 1020 is executable on one or multiple processors 1024, whichcan be connected over a bus 1026 to a storage medium 1028 (which canstore the decoded traffic data 1022) and a wireless interface 1030 toperform wireless communications with the electronic device 102.

The wireless access network node 108 can send the decoded traffic data1022 to another node for communication to an intended recipient of thedecoded traffic data 1022, which can be a device coupled to the datanetwork 112 of FIG. 1, for example.

The storage media 1010 and 1028 can include a random access memory (RAM)(e.g. dynamic RAM or static RAM), read-only memory (ROM) (e.g. erasableand programmable read-only memory (EPROM), electrically erasable andprogrammable read-only memory (EEPROM), or flash memory), and/orsecondary storage (e.g. magnetic or optical disk-based storage), and soforth.

In the foregoing description, numerous details are set forth to providean understanding of the subject disclosed herein. However,implementations may be practiced without some or all of these details.Other implementations may include modifications and variations from thedetails discussed above. It is intended that the appended claims coversuch modifications and variations.

What is claimed is:
 1. A method comprising: encoding, by an electronic device, traffic data as a collection of codes; sending, by the electronic device over a wireless link to a wireless access network node, the codes in random access resources, the codes providing an encoded representation of the traffic data; and dividing the traffic data into plural chunks, wherein the encoding comprises applying at least one encoding function to the plural chunks to produce the corresponding codes, wherein a size of at least one of the chunks corresponds to a number of codes available for encoding the respective chunk.
 2. The method of claim 1, wherein sending the codes in the random access resources comprises sending the codes in physical random access channel (PRACH) resources.
 3. The method of claim 1, wherein sending the codes comprises sending physical random access channel (PRACH) preambles.
 4. The method of claim 1, wherein the electronic device is a sensor device, and wherein encoding the traffic data comprises encoding measurement data collected by the sensor device.
 5. The method of claim 1, wherein the number of codes available is configured by signaling from the wireless access network node.
 6. The method of claim 1, further comprising: receiving, by the electronic device, a first uplink grant that specifies a first random access resource in a first transmission opportunity, wherein a first of the codes is sent in the first random access resource; receiving, by the electronic device, a second uplink grant that specifies a second random access resource in a second transmission opportunity, wherein the second uplink grant is responsive to the first code; and sending, by the electronic device to the wireless access network node, a second of the codes in the second random access resource.
 7. The method of claim 1, wherein sending the codes comprises sending the codes in-sequence or out-of-sequence.
 8. The method of claim 1, wherein encoding the traffic data comprises encoding the traffic data along with an identifier of the electronic device, wherein the encoded representation represents the traffic data and the identifier of the electronic device.
 9. The method of claim 1, wherein the traffic data is different from data communicated by the electronic device to obtain access of wireless resources of the wireless access network node.
 10. A method comprising: encoding, by an electronic device, traffic data as a collection of codes; sending, by the electronic device over a wireless link to a wireless access network node, the codes in random access resources, the codes providing an encoded representation of the traffic data; and dividing the traffic data into plural chunks, wherein the encoding comprises applying at least one encoding function to the plural chunks to produce the corresponding codes, and wherein: a number of codes available for encoding is the same for each chunk of the plural chunks, or a number of codes available for encoding a first of the plural chunks is different from a number of codes available for encoding a second of the plural chunks.
 11. A wireless access network node comprising: a wireless interface configured to receive, from an electronic device, a collection of codes in random access resources from an electronic device, the collection of codes being a representation of traffic data from the electronic device; and at least one processor configured to: produce the traffic data from the collection of codes, wherein the codes in the collection are from a first set of codes assigned for conveying traffic data; receive a further code; determine whether the further code is part of the first set of codes or a second set of codes assigned for contention-based random access; and in response to determining that the further code is part of the second set of codes, initiate a random access procedure.
 12. The wireless access network node of claim 11, wherein the at least one processor is configured to decode each of the codes of the collection to produce a respective chunk, wherein the chunks produced from the codes of the collection form the traffic data.
 13. The wireless access network node of claim 11, wherein the at least one processor is configured to define plural groups of electronic devices, and wherein the plural groups of electronic devices are assigned respective different sets of codes to use for encoding respective traffic data.
 14. The wireless access network node of claim 11, wherein the at least one processor is configured to identify distinct codes sent by plural electronic devices, and to assign further random access resources in response to the identified distinct codes.
 15. The wireless access network node of claim 14, wherein the further random access resources are assigned based on a number of the distinct codes sent by the plural electronic devices.
 16. The wireless access network node of claim 11, wherein the at least one processor is configured to cause truncation of original data to be transmitted by the electronic device, wherein the traffic data represented by the collection of codes is a truncated version of the original data to be transmitted by the electronic device.
 17. The wireless access network node of claim 11, wherein the at least one processor is configured to constrain use of random access resources for carrying traffic data from electronic devices, as part of a load balancing procedure.
 18. The wireless access network node of claim 11, wherein the at least one processor is configured to assign different transmission opportunities to different sensor devices.
 19. The wireless access network node of claim 11, wherein the traffic data is different from data communicated by the electronic device to obtain access of wireless resources of the wireless access network node.
 20. A wireless access network node comprising: a wireless interface configured to receive, from an electronic device, a collection of codes in random access resources from an electronic device, the collection of codes being a representation of traffic data from the electronic device; and at least one processor configured to produce the traffic data from the collection of codes, wherein the at least one processor is configured to selectively allocate further random access resources to a subset of electronic devices that are sending traffic data, wherein the selective allocation is based on a determination of whether codes received from the electronic devices meet one or more specified criteria.
 21. An electronic device comprising: a wireless interface to communicate wirelessly with a wireless access network node; and at least one processor to: encode traffic data as a collection of codes, wherein the traffic data is different from data communicated by the electronic device to obtain access of wireless resources of the wireless access network node; send, over a wireless link to the wireless access network node, the codes in random access resources, the codes providing an encoded representation of the traffic data, wherein the codes in the collection are from a first set of codes assigned for conveying traffic data; and send a further code from a second set of codes to use for performing a contention-based random access procedure to obtain wireless resources of the wireless access network node. 